We have expanded our investigations of photon migration in turbid biological media. Light diffusion in layered tissues was analyzed by using specially designed computer codes to enumerate probability densities of photons moving on a lattice. Other work has involved deriving mathematical expressions for the distributions of the depths at which photons travel. Facilities have been upgraded for performing quasielastic and dynamic light scattering studies. These have been used to further examine the effects of salts and pH on the assembly of supramolecular structures formed by the peptide hormones found within the neurosecretory vesicles of bovine pituitaries. Other studies with this equipment have involved the use of dynamic light scattering to measure parameters pertaining to the response of transiently bonded gels. We also have continued various studies involving neutron scattering from dense biological media.